I don't like how the default mail client automatically gives you access to my Hotmail account when you click on the envelope icon in the command bar (no password needed)... there is no security and even when I've signed out of my Hotmail you can still access it no problem through the command bar... did this automatically start happening after MSFT bought Hotmail and everything was switched over? How do I keep things secure?
If you are nervous about it, don't use it.... Also, you should have a password on your computer which will have to be bypassed first. Although an experienced hacker would be able to bypass that in two seconds using kon-boot, I seriously doubt that your average thief whom I assume you are thinking of would be able to bypass it. Furthermore, if you are still nervous I would recommend that you just use hotmail through your browser and request that it not save the password.
You can create a non-email login account if you want this behavior to stop as well. This would be like previous versions of Windows. They want you to use your Microsoft account so they can tie everything together and migrate your profile from device to device using skydrive.